Storm Goretti: homeowners warned of high-risk ‘triple threat’ to roofing as snow bomb hits

Roofing experts warn that the combination of rapidly-accumulating snow, fluctuating temperatures and 90mph winds could create a high-risk ‘triple threat’ scenario for both structural damage and water ingress.

As Met Office amber and yellow warnings take effect across England and Wales today, experts warn that the forecast heavy snow across the Midlands, Wales, Yorkshire and southern England could impose immediate, unexpected weight on flat roofs, placing them under uneven structural strain.

“Snow load is one of the most underestimated and dangerous threats flat roofs face,” said Lee Moore, specialist products manager at PermaRoof UK.

“If the predicted accumulations of up to 30cm of snow hit, this could place extreme, uneven stress on flat roofs, particularly as it compacts or starts to thaw. As temperatures fluctuate, it becomes standing water, dramatically increasing the weight load on the structure.

“On older or poorly maintained flat roofs, that extra weight can push the roof beyond its design limits, leading to deflection, structural damage and water ingress - or, in severe cases, sudden failure that isn’t always immediately visible.”

With recent storms and torrential rain already testing the resilience of even the most trusted waterproofing systems such as EPDM, which boasts all-weather durability and excellent resistance to standing water, experts stress the snowfall could expose hidden vulnerabilities that have gone unnoticed for years.

Key snow-related risks to flat roofs:

• Excess structural load - heavy, compacted snow can place extreme pressure on roof decks and supporting structures
• Deflection and sagging - even minor roof dips can worsen under snow weight, leading to long-term damage
• Blocked drainage outlets - snow and ice can prevent meltwater from draining properly
• Pooling and standing water - as snow melts, water can collect on flat roofs, increasing leak risk
• Freeze-thaw damage - meltwater that refreezes can exploit small cracks and joints, worsening existing faults

“When snow turns to water, the load on a roof can actually increase,” Moore explained. “One cubic metre of water weighs a tonne. If drainage is compromised, that excess weight can sit on a roof for days.

“Homeowners can take precautionary steps to reduce risk during snowfall, without putting themselves in danger - but concerns should be assessed and addressed by a qualified professional rather than tackled as a DIY task.”

Key advice: snow-smart actions for flat roofs:

• Visually monitor snow build-up from the ground, especially on flat roofs
• Ensure drains, outlets and gutters are clear before freezing conditions worsen
• Watch for signs of stress such as sagging ceilings, new cracks or doors sticking
• Do not climb onto the roof during icy conditions - this is extremely dangerous
• Act quickly if leaks appear, even small drips can signal trapped meltwater

As flat roofing specialists with more than 25 years’ experience, PermaRoof UK continues to advocate durable solutions designed for Britain’s changing climate.

“Your roof is your home’s first line of defence,” Moore added. “EPDM is robust, reliable and renowned for strong performance in adverse weather - but heavy snow should never be ignored.

“Awareness and preventative checks can avoid serious structural issues and costly repairs once the thaw begins. If you’re unsure about your roof’s condition, expert advice now could save thousands later.”